CEPHALOSPORINS= cefadroxil, Duricef ceFAZolin (sef-a-zoe-lin) Ancef cephalexin (sef-a-lex-in) Keflex

 Indications

Treatment of the following infections caused by susceptible

organisms: Skin and skin structure infections (including

burn wounds), Pneumonia, Urinary tract infections,

Bone and joint infections, Septicemia. Not

suitable for the treatment of meningitis. Cefadroxil:

Pharyngitis and/or tonsillitis. Cefazolin: Perioperative

prophylaxis, biliary tract infections, genital infections,

bacterial endocarditis prophylaxis for dental and upper

respiratory tract procedures. Cephalexin: Otitis media.

Action

Bind to bacterial cell wall membrane, causing cell

death. Therapeutic Effects: Bactericidal action

against susceptible bacteria. Spectrum: Active against

many gram-positive cocci including: Streptococcus

pneumoniae, Group A beta-hemolytic streptococci,

Penicillinase-producing staphylococci. Not active against: Methicillin-resistant staphylococci, Bacteroides

fragilis, Enterococcus. Active against some gramnegative

rods including: Klebsiella pneumoniae, Proteus

mirabilis, Escherichia coli.

Pharmacokinetics

Absorption: Cefadroxil and cephalexin are well absorbed

following oral administration. Cefazolin is well

absorbed following IM administration.

Distribution: Widely distributed. Cefazolin penetrates

bone and synovial fluid well. All cross the placenta

and enter breast milk in low concentrations. Minimal

CSF penetration.

Metabolism and Excretion: Excreted almost entirely

unchanged by the kidneys.

Half-life: Cefadroxil—60–120 min; cefazolin—

90–150 min; cephalexin—50–80 min (all areqin

renal impairment).

TIME/ACTION PROFILE (blood levels)

ROUTE ONSET PEAK DURATION

Cefadroxil PO rapid 1.5–2 hr 12–24 hr

Cefazolin IM rapid 0.5–2 hr 6–12 hr

Cefazolin IV rapid 5 min 6–12 hr

Cephalexin

PO

rapid 1 hr 6–12 hr

Contraindications/Precautions

Contraindicated in: Hypersensitivity to cephalosporins;

Serious hypersensitivity to penicillins.

Use Cautiously in: Renal impairment (dosagep

and/orqdosing interval recommended for: cefadroxil

and cephalexin, if CCr 50 mL/min, and cefazolin, if

CCr 30 mL/min; History of GI disease, especially colitis;

Geri: Dose adjustment due to age-relatedpin renal

function may be necessary; OB, Lactation: Half-life is

shorter and blood levels lower during pregnancy; have

been used safely.

Adverse Reactions/Side Effects

CNS: SEIZURES (high doses). GI: CLOSTRIDIUM DIFFICILE-

ASSOCIATED DIARRHEA (CDAD), diarrhea, nausea,

vomiting, cramps. Derm: STEVENS-JOHNSON SYNDROME,

rashes, pruritis, urticaria. Hemat: agranulocytosis,

eosinophilia, hemolytic anemia, neutropenia, thrombocytopenia.

Local: pain at IM site, phlebitis at IV site.

Misc: allergic reactions including ANAPHYLAXIS and SERUM

SICKNESS, superinfection.

Interactions

Drug-Drug: Probenecidpexcretion andqblood

levels of renally excreted cephalosporins. Concurrent

use of loop diuretics or aminoglycosides mayq

risk of renal toxicity.

Route/Dosage

Cefadroxil

PO (Adults): Pharyngitis and tonsillitis—500 mg q

12 hr or 1 g q 24 hr for 10 days. Skin and soft-tissue

infections—500 mg q 12 hr or 1 g q 24 hr. Urinary

tract infections—500 mg–1 g q 12 hr or 1–2 g q 24

hr.

PO (Children): Pharyngitis, tonsillitis, or impetigo—

15 mg/kg q 12 hr or 30 mg/kg q 24 hr for 10

days. Skin and soft-tissue infections—15 mg/kg q

12 hr. Urinary tract infections—15 mg/kg q 12 hr.

Renal Impairment

PO (Adults): CCr 25–50 mL/min—500 mg q 12 hr;

CCr 10–25 mL/min—500 mg q 24 hr; CCr 10 mL/

min—500 mg q 36 hr.

Cefazolin

IM, IV (Adults): Moderate to severe infections—

500 mg–2 g q 6–8 hr (maximum12 g/day). Mild infections

with gram-positive cocci—250–500 mg q

8 hr. Uncomplicated urinary tract infections—1 g q

12 hr. Pneumococcal pneumonia—500 mg q 12 hr.

Infective endocarditis or septicemia—1–1.5 g q 6

hr. Perioperative prophylaxis—1 g given 30–60 min

prior to incision. Additional 500 mg–1 g should be

given for surgeries 2 hr. 500 mg–1 g should then be

given for all surgeries q 6–8 hr for 24 hr postoperatively.

IM, IV (Children and Infants 1 mo): 16.7–33.3

mg/kg q 8 hr (maximum6 g/day); Bacterial endocarditis

prophylaxis in penicillin-allergic patients: 25

mg/kg 30 min prior to procedure (maximum dose1

g).

IM, IV (Neonates 7 days): 40 mg/kg/day divided q

12 hr.

IM, IV (Neonates 7 days and 2 kg): 40 mg/kg/

day divided q 12 hr.

IM, IV (Neonates 7 days and 2 k g): 60 mg/kg/

day divided q 8 hr.

Renal Impairment

IM, IV (Adults): CCr 10–30 mL/min—Administer q

12 hr; CCr 10 mL/min—Administer q 24 hr.

Cephalexin

PO (Adults): Most infections—250–500 mg q 6 hr.

Uncomplicated cystitis, skin and soft-tissue infections,

streptococcal pharyngitis—500 mg q 12 hr.

PO (Children): Most infections—25–50 mg/kg/day

divided q 6–8 hr (can be administered q 12 hr in skin/

skin structure infections or streptococcal pharyngitis).

Otitis media—18.75–25 mg/kg q 6 hr (maximum

4 g/day).

Renal Impairment

PO (Adults): CCr 10–50 mL/min—500 mg q 8–12

hr; CCr 10 mL/min—250–500 mg q 12–24 hr.

Availability

Cefadroxil (generic available)

Capsules: 500 mg. Tablets: 1 g. Oral suspension

(orange-pineapple flavor): 250 mg/5 mL, 500 mg/5

mL.

Cefazolin (generic available)

Powder for injection: 500 mg/vial, 1 g/vial, 10 g/vial,

20 g/vial. Premixed containers: 1 g/50 mL D5W, 2 g/

50 mL D5W.

Cephalexin (generic available)

Capsules: 250 mg, 500 mg, 750 mg. Tablets: 250 mg,

500 mg. Oral suspension: 125 mg/5 mL, 250 mg/5

mL.